Bipolar-Junction (BJT) transistors – UCSD ECE65 class notes http://aries.ucsd.edu/NAJMABADI/CLASS/ECE65/06-W/NOTES/BJT1.pdf
Jacob Millman, Microelectronics: Digital and Analog Circuits and Systems, McGraw-Hill, 1979 ISBN 0-07-042327-X, pp. 106–107 /wiki/Jacob_Millman
Douglas J. Hamilton, William G Howard, Basic Integrated Circuit Engineering, McGraw Hill, 1975, ISBN 0-07-025763-9, pp. 457–467 /wiki/ISBN_(identifier)
B. A. Boulter, The Multiple Emitter Transistor In Low Power Logic Circuits in Edward Keonjian (ed) Micropower Electronics, Elsevier, 2013, ISBN 148315503X, p. 105 ff /wiki/ISBN_(identifier)